I have stage four bowel cancer, and if you believe the stats I shouldn't be alive today.

But aside from the physical benefits, exercise is keeping me sane. Well, more sane.

It's without a doubt the pill we would all overdose on, if ever scientists work out how to pack it into tablet form.

Cancer Research UK is clear on the benefits of exercise, it can help reduce the risk of 13 different cancers.

But we are now seeing more and more evidence that shows exercise can help your mental health too – reducing the risk of depression.

And some studies have even shown it can help speed up your recovery after cancer treatment.

Personally, the mental health benefits are most important for me. It stops the dark thoughts creeping in.

Don't get me wrong, finding the effort to exercise is hard when you feel like sh*t, and you're sad about having a body that doesn't work.

It's a struggle when you're on new treatments, super-strength drugs with nasty side effects, just to stay alive.

And it feels impossible when you're angry at the fact you might not see your kids grow up.

Over Christmas I was so poorly from the side-effects of my new drugs that I actually thought I wasn't going to live to see February.

One evening, slightly delirious with a raging temperature, I wrote a list: The Sh*t I Need To Do Before I Die – and set myself a six-week time frame to get it all done.

Luckily, after two weeks of antibiotics and popping my running shoes back on, I haven't felt the need to start working through that list.

If I can run – no matter how slow it is – 5km, I figure I'm not dying today.

I take great pleasure in running to the Royal Marsden for my appointments as often I as can, even if it is to be told my tumours are growing or I'm too ill to have treatment.

It's my way of saying, 'I'll show you, cancer'!

But, it is hard to find the motivation, really, really hard. And it can be even harder when your body is working against you.

I need a kick to get going, and I'm the first to admit I'm a glory hunter.

If I haven't got a medal, sticker or pat on the back promised to me, my motivation stakes are at an all time low.

But dangle a shiny memento in front of me and just the thought of it can get me through the agony of a half marathon.

So this month I jumped at the chance to lead a team (which you can all join) and take part in Tri January, a campaign run by British Triatholon to encourage more than 5,000 people to swim, cycle and run their way through the month.

It's not about doing it all at once or being a hardcore athlete.

What is Tri January and how can you sign up?

IT'S simple… pick your team (mine), register and take part in Tri January with me.

The idea is to swim, cycle or run/walk through the month of January to achieve your chosen distance.

There's no set rules, you can make it work for you.

Swim one day, run the next, do what fits in best with your lifestyle.

Signing up is free of charge, just go to the website to join Team You, Me And The Big C.

It's about exercising at your own pace, taking it easy and doing little and often to progress.

You can sign up to be on my team, so why not try it?

I know it's hard to find the motivation, I'm writing this curled up under the duvet because the thought of getting dressed today was too much.

But, I will get up and I will put my trainers on and at least take the dog for a walk.

Because, every little bit really does count.

My new book F*** You Cancer is available to buy now – and gives a brutally honest view of what cancer is really like – buy it here now